Tracking epidemic Chikungunya virus into the Indian Ocean from East Africa.
The largest documented outbreak of Chikungunya virus (CHIKV) disease occurred in the Indian Ocean islands and India during 2004-2007. The magnitude of this outbreak led to speculation that a new variant of the virus had emerged that was either more virulent or more easily transmitted by mosquito vectors. To study this assertion, it is important to know the origin of the virus and how the particular strain circulating during the outbreak is related to other known strains. This study genetically characterized isolates of CHIKV obtained from Mombasa and Lamu Island, Kenya, during 2004, as well as strains from the 2005 outbreak recorded in Comoros. The results of these analyses demonstrated that the virus responsible for the epidemic that spread through the Indian Ocean originated in coastal Kenya during 2004 and that the closest known ancestors are members of the Central/East African clade. Genetic elements that may be responsible for the scope of the outbreak were also identified.
Kariuki Njenga
M
M
International Emerging Infections Program-Kenya, Centers for Disease Control and Prevention, Nairobi, Kenya.
Nderitu
L
L
Kenya Medical Research Institute, Nairobi, Kenya.
Ledermann
J P
JP
Centers for Disease Control and Prevention, Division of Vector-Borne Infectious Diseases, Fort Collins, CO 80521, USA.
Ndirangu
A
A
Kenya Medical Research Institute, Nairobi, Kenya.
Logue
C H
CH
Centers for Disease Control and Prevention, Division of Vector-Borne Infectious Diseases, Fort Collins, CO 80521, USA.
Kelly
C H L
CHL
Centers for Disease Control and Prevention, Division of Vector-Borne Infectious Diseases, Fort Collins, CO 80521, USA.
Sang
R
R
Kenya Medical Research Institute, Nairobi, Kenya.
Sergon
K
K
Field Epidemiology and Laboratory Training Program, Nairobi, Kenya.
Breiman
R
R
International Emerging Infections Program-Kenya, Centers for Disease Control and Prevention, Nairobi, Kenya.
Powers
A M
AM
Centers for Disease Control and Prevention, Division of Vector-Borne Infectious Diseases, Fort Collins, CO 80521, USA.
D000351:Africa, Eastern / Q000453:epidemiology; D018354:Alphavirus Infections / Q000453:epidemiology*; D000818:Animals; D002646:Chikungunya virus / Q000145:classification / Q000235:genetics; D002522:Chlorocebus aethiops; D017507:Comoros / Q000453:epidemiology; D017931:DNA Primers; D005784:Gene Amplification; D016679:Genome, Viral; D006801:Humans; D007630:Kenya / Q000453:epidemiology; D007668:Kidney; D010802:Phylogeny; D012367:RNA, Viral / Q000235:genetics / Q000302:isolation & purification; D014709:Vero Cells
D017931:DNA Primers; D012367:RNA, Viral